Systems which use cameras to inspect integrated circuit ("IC") leads for quality control purposes are known. These systems are typically computer controlled and include frame grabber circuitry for digitizing images of an IC under inspection for comparison in three dimensions to an ideal IC of the same type. ICs having leads which do not meet specified inspection tolerances are rejected.
Known systems typically have control software hard-coded to function with only a particular, single type of camera/mirror arrangement. Most often, the cameras in these systems are aligned directly above, directly below or in the plane of the IC in order to simplify the determinations of coplanarity, sweep and the like with minimal difficulty.
A disadvantage of these systems is that the required camera locations may not be available in some IC manufacturing lines. This disadvantage is exacerbated by the fact that changes to the IC line--e.g., to improve throughput or reliability, or to change over to a different IC package--may render the inspection system inoperable.
Other systems disadvantageously require particular line structure, such as a shadow plate or mirrored conveying channel, and thus can not be installed without modifying the IC line.
What is desired, therefore, is an IC lead inspection system which is easy to install on a variety of IC manufacturing lines and can accommodate a wide variety of camera angles. An inspection system providing high reliability and improved accuracy is also desired.